This invention relates generally to machines for the manufacture of building block and more particularly concerns a machine and a method for making blocks of pressed earth.
In my earlier U.S. Pat. No. 5,629,033, a pressed earth block machine suitable for the manufacture of flat-surfaced blocks was disclosed. However, the invention disclosed therein is not suitable for the manufacture of blocks having three-dimensional surfaces in the orthogonally oriented sides of the blocks. In some building applications, it is desirable that the blocks have a tongue and groove configuration in both their lateral sides for maximum strength between laterally adjacent blocks and in their upper and lower surfaces for maximum strength between vertically adjacent blocks. A three dimensional configuration in orthogonal faces presents new problems in the pressing of the block in the breech, the ejection of the block from the breech and the transfer of the ejected block out of the path of the breech without causing damage to the block or its three dimensional contours. These problems are in addition to the normal requirements in speed of manufacture of the blocks, consistency of size and density of the blocks and simplicity of operation and maintenance of the machine.
It is, therefore, an object of this invention to provide a machine and method for manufacturing pressed earth blocks which make pressed earth blocks of constant density and depth. Another object of this invention is to provide a machine and method for manufacturing pressed earth blocks which facilitate the rapid production of uniform earth blocks. Yet another object of this invention is to provide a machine and method for manufacturing pressed earth blocks which produce blocks which are tongued-and-grooved in block surfaces that are orthogonal to each other.
In accordance with the invention, a method is provided for making a block from pressed earth. A press foot is raised in a breech to a first level even with an open upper end of the breech. A feed drawer having an open lower end and filled with granular material or loose earth is moved laterally across a planar surface into registration over the breech. The press foot is then lowered to a second level in the breech to receive a volume of the loose earth from the feed drawer into the breech. The feed drawer is withdrawn laterally across the planar surface out of registration with the breech to remove or screed the excess loose earth from above the open upper end of the breech. A bucking foot is then lowered to close the upper end of the breech. The press foot is raised to a third level in the closed breech to compress the loose earth in the breech into a block. The bucking foot is then raised to a level higher than the top of the feed drawer to permit vertical ejection of the block from the open upper end of the breech into the lateral path of the feed drawer. Upon repetition of the first step of raising the press foot to the first level, a previously made block will be simultaneously raised into the lateral path of the feed drawer. Upon repetition of the second step of moving the feed drawer laterally into registration over the breech, the previously-made block will be simultaneously pushed out of the path of the bucking foot. Preferably, when the feed drawer is fully withdrawn laterally across the planar surface out of registration with the breech, the feed drawer will be aligned under a hopper storing loose earth and additional loose earth will be dispensed from the hopper to refill the feed drawer.
In making vertically and laterally tongue-and-grooved blocks, the press foot and the bucking foot have complementary three dimensional upper and lower surfaces, respectively, and the breech has complementary three dimensional opposite side surfaces. Preferably, the step of moving the feed drawer and simultaneously pushing the previously-made block is performed by abutment of a three dimensional face of the previously-made block with a leading face of the feed drawer.
The machine for making block has an orthogonal breech aligned on a Z-axis and open upper and lower ends. The press foot is aligned below the breech for vertical reciprocal movement along the Z-axis within the breech. The feed drawer is aligned laterally of the breech for horizontal reciprocal movement along a Y-axis and has an open lower end for dispensing loose earth into the breech. The bucking foot is aligned above the breech for vertical reciprocal movement along the Z-axis to open and close the upper end of the breech. A hydraulic cylinder moves the feed drawer across a surface coplanar with the feed drawer open lower end into and out of registration with the breech. A second hydraulic cylinder moves the bucking foot into and out of abutment with the open upper end of the breech. A third hydraulic cylinder raises the press foot to a first level even with the open upper end of the breech when the feed drawer is out of registration with the breech, lowers the press foot to a second level in the breech to receive a volume of loose earth when the feed drawer is in registration with the breech and raises the press foot to a third level within the breech when the bucking foot is in abutment with the upper end of the breech to compress the loose earth in the breech against the bucking foot and form a block of pressed earth.
Preferably, the breech is substantially rectangular in the X-Y plane with two-dimensional surfaces in its Y-Z side walls and complementary three-dimensional surfaces in its X-Z side walls to provide the lateral tongue-and-groove of the block. All preferably, the press foot and the bucking foot have complementary three-dimensional surfaces in their upper and lower X-Y walls, respectively, to provide the vertical tongue-and-groove of the block.
Preferably, the machine further includes a hopper storing loose earth and aligned above the feed drawer when the feed drawer is out of registration with the breech. An open upper end of the feed drawer admits loose earth into the feed drawer from the hopper. The feed drawer has a trailing plate coplanar with its open upper end for closing the hopper when the feed drawer is in registration with the breech.
It is specially preferred that the feed drawer has a fixed wall with a lower edge notched to pass over the three dimensional surface of the press foot and push an already made block out of registration with the breech during forward motion of the feed drawer and a hinged wall following the fixed wall with a level lower edge for screeding along the open upper end of the breech during rearward motion of the feed drawer and for swinging clear above the three dimensional surface of the press foot during forward motion of the feed drawer.